Gentlemen,

During electrical system checking of my 24 Volt IV-P, I measured the current draw by each of the high-current solenoids at 0.37 to 0.40 amps. I had expected a different draw for the “intermittent” (e.g. starter) and “continuous” (e.g. master power) relays based on previous LML discussions. Not finding what I expected, I checked a friend’s similar IV-P and found the same. All relays were provided by Lancair as part of various kits, and the main electrical panel was pre-built with the starter, master, ground power and avionics relays installed.

 

As a second (non-scientific) test, I powered up one of the relays to see how much heat it generated. After half an hour (on the bench/no cooling air), it was too hot to hold my finger on it, but not so hot as to burn my finger. It would seem that continuous operation would be acceptable.

 

Has anyone had any trouble with these? Should I be looking for a different relay for either the continuous or intermittent duty uses? As my system is configured, only the master power relays for #1 and #2 electrical systems are continuously powered. All others are intermittent. Bill Harrelson gave me some info on Blue Sea Systems E-Series electronic switches—a relay that apparently uses different engagement and holding circuits to substantially reduce the total electrical system draw. I really like the quality and specs on these units, but am reluctant to rebuild my electrical distribution panel at this late stage.

Any thoughts/comments most appreciated.

Bob Pastusek

N437RP at 95%+